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Katherine Heigl became a mom for the first time last year when she and husband Josh Kelley adopted their beautiful daughter Naleigh from Korea. And at Thursday night's ShoWest Awards in Las Vegas, where she was honored as Female Star of the Year, she told Access Hollywood's Billy Bush that motherhood has completely changed her life.

"It's a life altering experience," Katherine told Billy, who hosted the ShoWest Awards, of parenthood. "Everyone says that, you know, sort of intellectually, but you just don't know emotionally until you hold that kid in your arms and you go. 'Oh my God! I am responsible for you, for everything — to keep you safe, to keep you healthy, to keep you loved and sheltered.

"It's changed everything, it's changed my perspective on life and work and love and marriage and family," she added.

Katherine, who took time off of ABC's "Grey's Anatomy" last year after adopting Naleigh, said her time off was absolutely the right thing to do.

"I took three months off for family leave, which was the best thing I could have ever done for my family," she said. "And it changed how I was able to balance [work and home life] better."

The actress has a host of movies on the way including "Killers," which co-stars Ashton Kutcher and is due out on June 4, and "Life As We Know It," which pairs her opposite Josh Duhamel, and will be released on December 22, but Billy made sure to ask if she plans to continue on television as well.

"Your film career is on fire. Any more TV or is it all film from here on out?" Billy asked, referring to the rumors that surfaced last week that Katherine is done with "Grey's."

"Um, I don't know," she said. "I'm still on TV, still doing it, still enjoying it. And, yeah, it's just two totally different formats in terms of scheduling, timing, what it takes."

One thing Katherine is already scheduling is her preparation for the role of Stephanie Plum, the protagonist in a series of novels from Janet Evanovich, which she will bring to life on the big screen. And earlier this month, she revealed her first step in her Stephanie transformation by changing her blonde locks to a deep, dark, brown.

"Yes, the hair… I actually did it just sort of spontaneously for a role that is kind of in the future," Katherine, told Billy. "I don't know when we're going to start this movie, but it's based on the Janet Evanovich novels, that are [these] massive million best selling books, 15 of them…. and the character is a brunette.

"I'm attached and we were going to do this movie, but I just wanted the fans to know [how committed I am], because blonde Katie Heigl probably wasn't people's idea of Stephanie Plum from New Jersey," Katherine added.

Katherine said she wanted to go brunette early to get into the role of a bounty hunter with attitude from Trenton, N.J. and to make the fans of the series know she is committed.

"I just thought that I wanted to get them on board now; I can do this. I'm committing to her," Katherine told Billy. "I want you to know that I am not going to disappoint, or I'm going to try not to."